Method of cooling bread



Nov. 19, 1935. w. L. FLEISHER 2,021,772

' METHOD OF GVOOLING BREAD Fild April 22, 1933 5 Sheets-Sheet l INVENTOR. Walter L Flasher BY fi 5 A TTORNEYS.

Nov. 19, 1935; w. 1.. FLEISHER METHOD OF COOLING BREAD 3 Sheets-Sheet 2 Filed April 22, 1933 I INVENTOR.

Walter LF'lezsh er BY c A TTORNEYS.

- Nov. 19, 1935. w F 5 2,021,772

METHOD OF COOLING BREAD Filed April 22, 1953 3 Sheets-Sheet 3 INVENTOR,

wall r L.Flezshef A TTORNEYS.

mamas 19, 1935.

PATENT OFFICE rm'rnon F COOLING mum) Walter L. Fleisher, New City, N. Y.

6 Claims.

This invention relates to a method of and means for cooling bread rapidly, and more particularly, to ,a method. in which bread is cooled by the evaporation of moisture therefrom at low pressures.

The modern bakery, capable of turning out several tons of bread per day, has been mechanized and speeded up in almost every conceivable way. For example, the ingredients are automatically weighed, mechanically mixed, proofed in an automatically controlled atmosphere, cooked in automatic ovens, and sliced and wrapped in machines which are almost human. However, themethod of cooling the bread after it leaves the oven; a step which must be accomplished before the bread can be sliced and wrapped, has not changed materially in 2,000 years. Many coolers, of one type or another, have been devised, but the best of these requires between one and two hours to reduce the temperature to the desired point. unusual and diflicult problems, arising largely by' reason of the chemical changes taking place in the bread during cooling. The structure of baked bread is. composed of cells of starch and protein and these. cells set up definite resistance to rupture to? a definite point, of which the temperature is an indicator. Furthermore, there is a definite vapor changein the bread as it cools, until it reaches a point of equilibrium. Bread may be deemed to breathe as it cools from oven temperature to this point of equilibrium, and the pressure of the vapor is outwardly as the temperature of the loaf decreases from oven temperature to about 135 degrees. Below that point the pressure of the atmosphere is greater than the outward pressure of the vapor in the bread.

This may be cdnsidered the point of equilibrium} and at this point the cell structure is such that in order to remove moisture from the bread at a relativehr rapid rate, the subjection of the bread to a pressure less than atmospheric is necessary. Otherwise, cooling below this point will be carried on very slowly and only by conduction, radiation and convection. For example, the bread leaves the oven at approximately 212 F. Within ten minutes, it will cool by natural radiation and convection. to about 130, but the time required to cool by' natural radiation and convection from" about 130? to about 85 to 90,

the temperature at which bread may be wrapped,

is frequently as much as one and a half hours. Further, rapid 'coolingis conducive to-case hardening of the crusts, which case hardening tends to hold the heat and moisturewithin the bread.

This cooling step presents manyv Application April 22, 1933, Serial'No. 667,327

Again, the amount of moisture which may be removed without affecting the taste of the bread must be controlled within very close limits in order that the quality and taste of the bread may not vary. Also, the formation of moisture on the crust, termed sweating, must be avoided; otherwise, a condition conducive to the formation of mold will result.

The general object of the invention, therefore, is to cool bread rapidly, but in conformance with 10 the requirements as set forth above. Another object of the invention is to provide a method in which the bread may be cooled internally, as well as externally.

A further object of the invention is to utilize the moisture which must be withdrawn from the bread as a cooling agent.

Still another object is to prevent the mold forming spores into the bread.

Another object of the invention is to provide a method of cooling bread rapidly which is continuous, thereby preventing the piling up of bread in the cooling stage.

A feature of the invention resides in the provision of a machine having a number of bread as cooling compartments into certain of which compartments bread-may be loaded and from other of which it may be withdrawn at predetermined intervals without aifecting the operation of the process in the other chambers. I n

Another feature resides .in the provision of a plurality of small bread cooling chambers which are automatically brought under the influence of the cooling -mechanism in suc cesslon, in such a entry of manner that the load on the mechanism is prac- I tically constant.

Another feature of the invention resides in the provision of a machine in which the bread is brought under the successive influence of sevr eral cooling mechanisms. 40

Another feature of the invention resides in the provision of a machine which lifts the bread into the cooling chambers, cools it, and automatically ejects the loaf. at the correct time.

Still another feature resides in the provision of an extremely simple distributor which controls the operation of the cooling mechanism or mechanisms.

Other objects and features, relating to efficiency, economyand simplicity, will be more apparent from the description, to be read in connection with the accompanying drawings, in

which: a

Fig. 1 is an elevation, partly in section, of 5 ne form of apparatus designed to carry out the 0 method of the invention, a plan view of a-portion of the ap-' 18. 2 is aratus of Fig. 1,

Fig. 3 is a plan view of the distributor shown in section in Fig. 1,

Fig. 4 is an elevation, partly in section, of another form of apparatus adapted to carry out the method of the invention, including a portion of the conveyor, lifting mechanism and the like,

Fig. 5 is a plan view of the distributor adapted to be used in connection with the apparatus of Fig. 4,

Fig. 6 is a plan view of a portion of the conveyor of Fig. 4,

Fig. 7 is a sectional elevation of still another form which the apparatus may take,

Fig. 8 is a view, in perspective, of a portion of Fig. 5 adapted to cooperate with the distributor of Fi 9.

Fig. 9 is a sectional view. of the distributor, taken on line P9 of Fig. 'i, and M Fig. 10 is a sectional elevation taken on line ill-ill of Fig. 7.

In the cooling of bread, it is necessary to remove a certain amount of its water content in order that all the bread may beof consistent quality and taste, and to increase its keeping quali For example, from a 22 ounce loaf, approximately .5 ounce of water must be removed. Generally, this water is allowed to evaporate, un-

der atmospheric pressure, as the bread cools, and

in so doing the water absorbs heat. If the bread is placed in a vacuum chamber, the water will be evaporated much more rapidly, and at a temperature corresponding to the absolute pressure in the vacuum chamber. By way of illustration,

if the bread is subjected to a vacuum of 29.56

inches of mercury (.3625 inch of mercury absolute) the water will evaporate at 50 F., and in sodoing, will absorb 1063.3 B. t. u./pound.

Essentially, applicant's cooling process comprises two steps, namely, a first step in which air after passing through a spore collecting filter, is blown over the bread to cool it from 212 to about 130 its equilibrium point as above described,

and a second step in which the bread, after the preliminary cooling, is subjected to a-vacuum, thereby causing the water contained in the bread to evaporate ata reduced temperature. If this process is uncontrolled, the amount of moisture removed will exceed the prescribed .5 ounce. To eifect a control, thus limiting the moisture withdrawn, the bread is subjected to successively different'pressures. For example, the bread may be subjected first to a vacuum of 28.89 inches of mercury, corresponding to 80? F., and then to a vacuumof 29.56 inches of mercury, corresponding to a 50 F. boilingpoint. In certain other cases, particularly those in which a thick crust has formed, it may be desirable to reverse the order of application of these pressures, subjecting the bread first to the lowest pressure and completing the cooling at some higher pressure. A further step in the control may be accomplished by providing a controlled volume of free'water within the vacuum chamber. when the pressure within the chamber is reduced, this free water will evaporate and come into intimate contact with the surfaces otthe bread to give certain definite and desired results; i. e., (1) evaporation withintheloaiwillberetarded. (2) theexternal the crusts will be maintained in a 80ft state,

cake icing and coated candies.

In those cases where both features of control are used, to wit, difierent stages of vacuum, and the utilization of free water in the chambers, apparently it ismost beneficial to evaporate all of the free moisture in the first vacuum stage, 5 allowing the second. vacuum stage to complete the cooling and to harden? and dry the bread crusts.

While the process is primarily designed for bread cooling; it has been found to give very ex 1o cellent results when applied to the hardening of In these applications, the second step, evaporating free moisture within the vacuum chamber, is of particular importance for the reason that the amount of moisture which may be evaporated from the icing or coating is very limited. Further, the direct contact of cold vapors with the icing causes an almost instantaneous hardening which results in ings, in which similar designations refer to similar parts, numeral l2 represents a cylindrical casting suitably mounted for rotation about ver- 25 -tical shaft II, on ball bearings H. The lower face of casting I3 is provided with a plurality of radially arranged chambers l5, each of which is adapted to contain a loaf of bread I 8.

The chambers I5 are provided with individual unconstricted passageways II, which passages terminate in holes l8 arranged radially, on a common circle, in the upper face of the casting. Mounted on the upper face of the casting, covering holes II in a manner to be hereinafter de- 85 scribed, is a stationary distributor I9. The edges 20 of the distributor are adapted to fit within an indentation 2| on the upper face of casting l2, and to float an oil; mercury, or other sealing liquid, contained in 2|, to the end that casting l2 may berotated, without allowing air to be intaken around the edge of the distributor. The distributor comprises generally a circular block having a plurality of grooves in its lower face, which grooves are adapted to register with certain of the holes I. in the upper face of casting l2. In the distributor of Fig. 3, groove 22 is provided with a 'passage, or a supplying steam to apressure reducing nozzle (not shown) within the head. An outlet diffuser 29 connectsthe inlet diffuser with a condenser (Fig. 4) in a well known manner. Steam passing through the nozzle is reduced in pressure and operates to create a vacuum in passage 26 as is well understood.

Plates ll cover the'chambers II to preclude the admission of air at this point. Plates 3|, preferably, are upset'as illustrated in Fig. 1, for the dual purpose of giving increased strength to withstand the pressure which is exerted on their lower faces, and to provide an{ indentation in which free water may be retained. Frequently, it is desirable to provide a-mesh screen above the indentation to support the loaf of breadout is of contact with the water. Other water changed by breaking groove 22 of Fig. 3 into two or more separate grooves. In the distributor of Fig. 5, groove 32 .communicates with conduit 33 through passage 34, while groove 35 connects with conduit 36 through passage 31. Groove 24 of Fig.-5 is identicai with 24 of Fig. 3, and

gives access, through a passage not illustrated,-

to atmospheric pressure, Conduit 33 joins avacuum pump 38 (illustrated as a steam ejector) adapted to operate at one low pressure, whereas conduit'36 joins a second vacuum pump 33, designed to operate at a difi'erent low pressure.

Fig. 4 also shows a conveyor, generally designated 4|), either of the chain, roller or other desired type, which is adapted to convey bread to the cooler. As illustrated (Figs. 4 and 6), plates 3|, each of which supports a'loaf of bread, are brought into proximity to chambers l5 by conveyor. 40, whereupon at a prescribed time, plunger 4i lifts a plate ill and its loaf, into the chamber in a well known manner. Prior to entry into chamber IS, a prescribed quantityof water may be admitted into the depression in the plates from tank 42. Applicant contemplates having each plate trip a valve to admit the water in prescribed quantities at the proper time.

Fig. 7 shows a further variation of the apparatus of Figs. 1 and 4, in which the vacuum chambers are arranged in horizontal position. In

this arrangement, a cylindrical casting 42 ismounted for rotation about a horizontal axis, suitably supported on bearings 44, and driven by a motor 45. The shaft may be tapered, ii desired,

intervals of '90", three chambers constituting a set, are shown. In practice, however, where this type of apparatus is used, the diameter of 43 will be greatly increased to provide a number oil-sets ofchambers l5. Each set of chambers i5 is provided with a passageway 46, which passage extends through the shaft 41, and terminates in a hole, or slot, (Fig 8). A distributor 43, an edge 50 of which fits into a groove on shaft 41 to form a seal, surrounds the end of shaft 41 and covers slots 48. The inner face of the distributor is provided with a plurality of grooves adapted to registerwith the slots 43, one of which grooves, Si, is in communication with a vacuum pump 52, while a second groove 53 is in communication with the atmosphere. From the description of Figs. 4 and 5, it is evident that groove 5| may be broken into a..plurality of grooves, each of which communicates with a separate vacuum The operation of the device-is best understood from a consideration of Figs. 1, 4, and 6, assuming the casting I2 is rotated as by a motor, that to approximately 130, reaching its equilibrium plunger 4| is operated by a cam in timed relation to the movement of i2, and that the vacuum pump is, or pumps are, in operation. A loaf of bread, as it leaves the oven, is placed on each cover plate 3|. The conveyor 40 carries the plates and bread through a tunnel, or other suitable device, in which filtered air is blown over the bread. Within approximately ten minutes, the

temperature of the bread will drop from 212 F.

10 point. "As each plate 3| passes tank- 42, a prescribed quantity of water is deposited on the plate, and each plate as it comes beneath the casting-i2 is lifted by plunger 4| into a chamber IS. The distributor is so arranged that hole l8 of the chamber directly above plunger 4| is in register. with atmospheric groove 24. When the plunger reaches the top of its stroke, plate 3| is in engagement with the lower faceof the casting, and by rotation of the casting, hole |8 is just registering with vacuum groove 22. The pressure in chamber l5 will be reduced instantly, hence, atmospheric pressure will hold plate 3| firmly in position, and the water, both in the bread itself and on the plate, will begin to boil as was previously explained. The speed of rotation of casting I2 is so regulated that as hole I3 approaches the end of groove 22, the bread will have cooled to the desired temperature. Hence. further rotation of i2 carries hole I8 out of register with groove 22 and into register with groove 24. Groove 24, being under atmospheric pressure, breaks the vacuum, whereupon plate 3| and its loaf of bread fail by gravity into a suitable receptacle, from which theloaf will usually be con- 3 veyed to the slicing and wrapping machines, while the plate 3| will be returned to the oven to receive another loaf. Continued rotation of i2 brings chamber l5 over plunger 4|, whereupon the described operations are repeated.

For purposes of illustration, the cycle has been described with respect to one chamber only, but it is apparent that as each succeeding chamber comes over the plunger 4|, it is loaded; in'an identical manner.

The operation of the apparatus of Fig. 4 is identical with that of Fig. 1, except that hole L8 registers first with groove 24, then withgroove 32, and then with groove 35, returning toregister with groove 24 to completethe operating cycle.

- In the apparatus of Fig. 'l, the difierence is-not in the mode of operation, but in details of the machine, 1. e., several leaves 01 bread must be simultaneously loaded into a plurality of chambers, the cover plates are curved to conform to the periphery of the cylinder, and slots 43, corresponding to holes I3, register with cylindrical grooves 5| and 53 corresponding to grooves 22, and 24' of Fig. 1. In operation, one set of chambers I5 is loadedwhen its corresponding slot 4360 is registering with atmospheric port 53, the cylinder rotates to advance the slot out of register with 53 and into register with vacuum slot BI, and when the bread is sufilciently cooled, slot 43 again registers with atmospheric port 53, the set of chambers empties by gravity, and a plunger corresponding to 4| reloads the chambers to begin a new cycle. 1

It is well recognized that certain types of bread,

because of inherent characteristics, take longer 7 to cool than do others. For example, French bread, with its hard, thick crust, is more dimcult to cool than is soft American bread. Similarly', rye bread, whole wheat bread, and raisin bread each require diiierent lengths '02 time to cool. Further although not usual, different lots of the same type of bread may vary, and hence, require a diflerent cooling time. This diiiiculty .may be overcome in one of these ways, or by a combination of the'several ways. For example, a reduction in speed of the rotating casting results in subjecting the bread to the cooling action for longer periods 01' time. Similarly, an increase in the degree'of vacuum speeds up the cooling process. Likewise, a variation in the amount of free moisture placed on plates 3| acts to vary the rate of cooling, In any events thermostat placed in one of chambers 15, and subject to changes in bread temperature, can be depended upon to accomplish the desired variation, e.*g., varying the speed of motor 45, varying the degree of vacuum by varying the action of the pump, or varying the valve controlling flow of water from tank 42 to plates 3|.

While the apparatus has been described in connection with the cooling of bread, it is apparent that .a change in the size and shape of chambers i5 is all that isnecessary to convert the described device into one for hardening the icing of cakes, candy, for the refining of sugars generally, or for other purpwes in accordance with applicant's method.

It is apparent that once the machine is placed in operation, the load on the vacuum pumps is practically constant. The chambers are small, hence, as each succeeding chamber comes into register with the vacuuin groove, only a small quantity 01 air must be withdrawn. Further, it is evident that the pumps arenever in direct com- Having described my invention, what I claim as new and desire to secure by Letters Patent 01'. the United States, is:

1. A method of 0001 118 bread which comprises evaporating water contained in the bread; with- 5 drawing the vapors through the crusts of the bread, simultaneously evaporating. other water not contained in the bread and passing the resulting vapor in contact with the outer crusts of the bread, both evaporating steps being accomplished at pressures substantially below atmospheric.

2. A method 01' cooling bread which comprises evaporating the water contained in the bread at pressures less than atmospheric, simultaneously boiling other water at substantially the same pressures and passing the vapors of said other water in contact with the surfaces of said bread to control the rate 01' evaporationwithin the bread.

3'. The method of cooling bread which comprises partially cooling the bread by passing air thereover, and completing the cooling by evaporating water at pressures less than atmospheric and passing the resulting cold vapors in contact with the surfaces of the bread. l

4. The method of cooling bread which comprises subjecting the bread to pressures less than atmospheric, withdrawing vapors from within the bread, and passing other vapors over the outer surfaces of the bread to control the rate of vapor withdrawal from the inside of the bread.

5. The method of cooling bread which comprises subjecting the bread to a first degree of vacuum,

withdrawing vapors from the inside of the bread, simultaneously passing other vapors in contact 5 with the outer surfaces or the bread to control the rate of vapor withdrawal, and subjecting the bread to a second degree of vacuum to dry the crusts thereof. M

6. A method of cooling bread which comprises 40 a first step of cooling the bread to a temperature between degrees and degrees by radiation and convection, and a second step in which the bread is subjected to pressures substantially less than that of the atmosphere.

- WALTER L. FLEISHER. 

